Industrial vacuum apparatus

ABSTRACT

This invention provides a mobile vacuum unit comprising a mobile frame on which a collection box is mounted. Snorkel intake means is adapted to draw air and entrained materials into the box through suction, and the box is adapted to dump collected materials at intervals. From the box an outlet leads to a two-way separating valve, and two further branches proceed from said valve. The first branch is utilized when the material coming from the collection box has a high liquid content, while the second branch is used for materials with a low or negligible liquid content. The first branch includes means, such as liquid swirl means, for separating liquid and entrained particulate matter from the gas in the material coming from the collection box, while the second branch passes the mixed material through a bag filter unit. Both branches re-combine at a two-way combining valve, and the outlet from the latter is in communication with the suction inlet of an air-pump, which exhausts through muffling means to the atmosphere.

Unite States Patet 1191 Wurster 1 INDUSTRIAL VACUUM APPARATUS [75] Inventor: Wilfred A. Wurster, Niagara Falls, Ontario, Canada [73] Assignee: Walkee Vacuum Services Ltd,

Ontario, Canada 22 Filed: May 15, 1973 21 Appl. No.: 360,538

[52] US. Cl 15/326, 15/340, 15/353, 55/228, 55/229, 55/237, 55/258, 55/260,

[51] Int. CL. Bld 50/00, B04c 5/185, BOld 47/00, B04c 9/00, B01d 46/00 [58] Field 01 Search 55/235, 276, 302, 309, 55/312, 314,315, 318, 319, 341, 459, 430,

[56] References Cited UNITED STATES PATENTS 1,103,509 7/1914 Harker 55/322 X 1,793,460 2/1931 Binkley 55/325 2,690,813 /1954 Diebold 55/324 2,824,335 2/1958 Moffat /353 X 2,830,674 4/1958 Dolf et a1 /315 X 3,300,807 1/1967 Berkowitz 15/340 3,404,470 10/1968 Raiti 37/12 3,404,776 10/1968 Shaddock 209/ 3,406,423 10/1968 Young 15/340 3/1969 Daneman 15/326 [451 Oct.22, 1974 Primary Examiner-Dennis E. Talbert, Jr. Attorney, Agent, or F irm-Sim & McBumey 5 7] ABSTRACT This invention provides a mobile vacuum unit com prising a mobile frame on which a collection box is mounted. Snorkel intake means is adapted to draw air and entrained materials into the box through suction, and the box is adapted to dump collected materials at intervals. From the box an outlet leads to a two-way separating valve, and two further branches proceed from said valve. The first branch is utilized when the material coming from the collection box has a high liquid content, while the second branch is used for materials with a low or negligible liquid content. The first branch includes means, such as liquid swirl means, for separating liquid and entrained particulate matter from the gas in the material coming from the collection box, while the second branch passes the mixed material through a bag filter unit. Both branches re-combine at a two-way combining valve, and the outlet from the latter is in communication with the suction inlet of an air-pump, which exhausts through muffling means to the atmosphere.

3 Claims, 3 Drawing Figures INDUSTRIAL VACUUM APPARATUS This invention relates generally to vacuum cleaning apparatus, and has to 'do particularly with a mobilevacuum unit suitable for use in industrial applications where large amounts of wet or dry particulate matter not to be removed.

BACKGROUND OF THIS INVENTION paratus, it is among the objects of this invention to provide a mobile vacuum apparatus having a collector box constructed in such a way' as to permit very efficient dumping of virtually all mattercollected in the box,re-

a snorkel or hose draws the waste material up to an inlet port of the collector box, within which a primary separation of heavy solid materials from the lighter, airborne materials takes place. The heavy material falls to the bottom of the collector box, while the lighter material is withdrawn from the collector box along with air and passes through the mechanical filter, if one is provided. The outlet'fromthe filter is connected to the intake of the air-pumping means, and the outlet from the latter is either exhausted directly to the atmosphere or is routed through a silencer (muffler) component before being blown into the atmosphere.

DRAWBACKS'OF THE PRIOR ART The apparatus of the prior art generally has two problem areas which it is the purpose of this invention to correct. The first problem area relates to the inability of conventional machinery to adapt itself efficiently to both of the extreme conditionsunder which apparatus 'of this sort is required to function. The one extreme condition is that in which the waste material to be removed has a very high liquid content; the other extreme condition is that in which the waste material to a be removed is essentially dry, and free from any liquid content. Naturally, many industrial situations which call for the use of mobile vacuum apparatus fall somewhere between the'twoextreme conditions.

The other problem area in conventional apparatus relates to the collector box itself, in which the largest and heaviest particles in the material being evacuated are collected. In the case of both dry and wet materials, there is a tendency for the collected matter in the bottom of the collector box to form a sticky mass with a strong tendency to adhere to itself and to the insidesurfaces of the collector box, such that attempts to dislodge or dump the collected material out of the collec- OBJECTS OF THIS INVENTION In view of the above shortcomings of the prior art apgardless of the moisture content or stickiness thereof.

It is also among the objects of this invention to provide a mobile vacuum apparatus capable of removing both wet and dry waste material with a high degree of efficiency.

GENERAL DESCRIPTION OF THIS INVENTION Accordingly, this invention provides a collector box for a mobile vacuum unit, the collector box being mounted to the vacuum unit for pivotal movement about a horizontalaxis between a collection position and a dumping position, and having a dumping opening through which materials contained in the box can exit gravitationally when the box is in the dumping position,

a closure member adapted to cover the opening when the box is in the collection position and to uncover the openingwhen the box is in the dumping position, the box having a first chamber adjacentto and in communication with said opening, a second chamber adjacent the first chamber and divided therefrom by a panel depending gravitationally from a horizontal pivot axis, the panel substantially isolating lower portions of the chambers from one another when the box is in the collection position but permitting communication between the lower portions of the chambers when the box is in the dumping position, an air outlet from the second chamber through which air can be withdrawn by suction, an air inlet into said first chamber through which air and entrained materials can be admitted due to suction, a passage for air from the first to the second chamber above the said panel, the first chamber being adapted to accumulate coarse solids entrained in the entering air, the second chamber containing separation means to facilitate the separation from the air of liquids and finer solids, the second chamber being so disposed with respect to the first chamber that upon pivoting of the box from the collection to the dumping position, the material collected in the second chamber tends to pass gravitationally into the first chamber under said panel, thus irrigating the coarser material in said first chamber and facilitating its dislodgement through said dumping opening.

This invention further provides a mobile vacuum unit, comprising a mobile frame, a collector box mounted on said mobile frame, a snorkel communicating with said collector box and adapted to draw air and entrained materials into said box through suction, said box being adapted at intervals to dump materials contained therein, an outlet from said box leading to a twoway separating valve; a first conduit leading from said valve to the intake of a swirler unit having means for capturing air-entrained particles in a rotating stream of liquid, the outlet from said swirler unit leading through a second conduit to the tangential inlet to a demister unit having an exhaust outlet for gas at the top and a collection chamber for liquid at the bottom, pump means for recirculating liquid from said collection chamber to said swirler unit to enter said rotating stream of liquid, a third conduit from said exhaust outlet to one inlet of a two-way combining valve, a fourth conduit leading from said two-way separating valve to the inlet of a bag filter unit, a fifth conduit leading from the outlet of said bag filter unit to the other inlet of said two-way combining valve, the outlet of said two-way combining valve being in communication with the inlet to a screen filter unit, the outlet of said screen filter unit communicating with the suction inlet of an air-pump, the outlet of said air pump exhausting through muffling means to the atmosphere, and means for powering said air-pump.

GENERAL DESCRIPTION, OF THE DRAWINGS One embodiment of this invention is shown in the accompanying drawings, in which like numerals denote like parts throughout the several views and in which:

FIG. 1 is a perspective view of a mobile vacuum unit in accordance with this invention;

FIG. 2 is a schematic view of the several components of the mobile unit of FIG. 1; and

FIG. 3 is a detail view of a component thereof.

PARTICULAR DESCRIPTION OF THE DRAWINGS In FIG. I, a vacuum unit shown generally at It) is seen to include an elongated frame I2 adapted to ride on two sets of wheels 14 (only one set visible in FIG. I), a collector box 15 mounted on the rear of the frame 12, a gasoline or diesel engine I6 powering an airblower 18, a silencer 20, and intermediate filtering and separating apparatus seen generally at 22.

Certain parts of the overall unit are not visible in FIG. I because of the mounting arrangement, and attention is now directed to FIG. 2, in which all essential components of this invention are schematically illustrated.

A description will first be given of the basic arrangement and operation of all the components together, following which a detailed description of the construction and function of the collector box 15 will be set out.

In addition to the components already listed with reference to FIG. 1, FIG. 2 shows a snorkel 24 which is flexible and is adapted to extend downwardly into a pit container, etc. 26 from which waste materials 28 are required to be removed. As can be seen, the downstream end of the snorkel 24 communicates with an inlet opening 29 of the collector box 15. The outlet opening 30 of the collector box I communicates with the inlet of a two-way separating valve 32. The separating valve 32 includes a vertically adjustable separating disc 33 adapted to be moved between a first position in which it is shown in FIG. 2, and a second position in which it is urged against an upper valve seat 34. As illustrated, the disc 33 is located against a lower valve seat 36. The disc 33 is adjustable by means of a threaded shaft 37 and a manual crank 38 at the lower end of the shaft. From the drawing it is easy to see that when the disc 33 is in its lowermost position all materials passing through the outlet opening 30 of the collector box and into the separating valve 32 are routed along a first conduit 40, whereas when the disc 33 is in its uppermost position such materials are routed through a further conduit 42.

When the separating valve 32 is in the position shown, the material passing through the outlet opening 30 of the collector box 15 passes upwardly along the first conduit 40 and enters a swirler unit 44 which may be of conventional construction. The essential function of the swirler unit is to mix the incoming particle-laden gas with a liquid (preferably water) in a highly agitated state, whereby the liquid will entrain some at least of the particles originally in the gas. Liquid is provided to the swirler unit 44 along at least one pipe 45 adapted to enter the upper portion of the swirler unit 44 tangentially. From the upper portion, the swirler unit 44 converges conically downwardly as shown at 46, and debouches into a second conduit 47 leading to a demister unit 49. High pressure liquid is expelled tangentially into the upper portion of the swirler unit 44 through the pipe 45 and the liquid continues to rotate within the conical portion 46. As the rotating liquid exits into the second conduit 47 it is in a highly agitated state, and of course the dust-laden gas (air) passing into the swirler unit 44 from the first conduit. 40 is mixed with this agitated liquid. As a result, there is an intimate contact between the liquid, the gas and the particles originally contained in the gas during passage through the second conduit 47. This results in a large portion of the originally gas-borne particles being entrained in the liquid.

The second conduit 47 enters the demister unit 49 tangentially (although this is not illustrated in the essentially schematic drawing of FIG. 2), and the primary function of the demister unit 43 is to separate the now at least partially cleaned gas (air) from the liquid passing along the second conduit 47. Because of the tangential inlet, all of the material entering the demister unit 49 is thrown centrifugally against the cylindrical wall of the demister unit 49, and inertial forces tend to cause the liquid to hug the wall while the gas or air passes into the center of the demister unit 49 and exits upwardly into and through a third conduit 50 which communicates at its downstream end with one inlet 52 of a two-way combining valve 54.

The liquid separated out in the demister unit 49, along with any particulate material entrained in the liquid, passes down along the demister'unit and through a lower outlet into a liquid collection chamber 56. A pump 58 withdraws liquid from the collection chamber 56 and pumps it through a pipe 60 into a first compartment 61 of a container 62. The container 62 is provided with a vertical weir 63 which permits spilling of the liquid from the first compartment 61 into a second compartment 64 once the liquid in the first compartment 61 has risen sufficiently high. A further pump 66 withdraws liquid from the second compartment 64 through a pipe 67 and pumps it at high pressure through the aforementioned pipe 45 leading tangentially into the upper portion of the swirler unit 44.

It will be appreciated that the liquid collection chamber 56 and the first compartment 61 of the container 62 both act to some degree as settling chambers in which the larger and heavier particles entrained in the liquid in the swirler unit 44 can settle out. Means are provided (not shown in FIG. 2) for periodically cleaning out the liquid collection chamber 56 and the first compartment 61. These means are visible in FIG. 1 and include a first cleaning door 68 and a second cleaning door 70. The first cleaning door 68 in FIG. 1 is located toward the bottom of the liquid collection chamber 56, while the second cleaning door 70 is located at the bottom of the container 62.

Returning now to FIG. 2, it will be seen that the twoway combining valve 54 is essentially identical in construction and operation to the two-way separating valve 32. Thus, rotation of the hand crank 72 of the combining valve 54 is adapted to raise and lower the separating disc 73 between two extreme positions, in one of which (that shown) the third conduit 50 communicates with the outlet 75 of the two-way combining valve 54.

As seen, the outlet 75 of the two-way combining valve 54 communicates with the inlet of a screen filter unit 77, which is not considered essential to the invention but may be provided if desired for any reason. Naturally, the greater the number of filtering components located between the snorkel 2 1 and the air-blower 18, the greater will be the purity of the air passing through the air-blower, and the longer will be the life of the latter. From the outlet 78 of the screen filter unit 77, the air simply passes through the air-blower l8, thence through the silencer 20, and from there is exhausted to the atmosphere at 80.

If both the separating valve 32 and the combining valve 54 are now adjusted to the other position for each, that opposite to the positions in which they have been drawn in FIG. 2, it will cause the material passing through the outlet opening 30 of the collector box to pass downwardly through the conduit 42, which will be referred to hereinafter as the fourth conduit. Material passing into and along the fourth conduit 42 enters the lower chamber 82 of a dust collector 83 which may of standard construction. In order for gas to pass from the lower chamber 82 into the upper chamber 84 of the dust collector 83, it must first pass through walls of a plurality of separator bags 86, the interiors of which communicate with the upper chamber 84. In passing through to the interior of the separator bags 86, the dust in the air is stopped and collects on the outside of the separator bags 86. As is usual, the dust collector 83 is provided with blow-back means (not shown) which fires a short blast of high pressure air into the interior of the separator bags for the purpose of cleaning the exteriors of accumulated material. The accumulated material thus dislodged falls down to the bottom of the lower chamber 82, and can be removed therefrom either continuously or periodically by means of worm conveyors such as that shown schematically at 88. Because the construction of the dust collector 83 is conventional, it has not been shown in great detail in FIG. 2. From the upper chamber 84 of the dust collector 83, the cleaned air passes into a fifth conduit 90, which in turn communicates with the other inlet to the combining valve 54. Provided the separating disc 73 is in the uppermost position, the air passing along and through the fifth conduit 90 passes directly into the screen filter unit 77, and thence through the air-blower l8 and silencer 20, just as before.

It will thus be appreciated that the overall mobile vacuum unit just described is capable of processing material-laden air through either one of two alternative filtering paths. The path which includes the swirler unit 44 and the demister unit 49 is preferred when the air and the dust passing through the outlet opening 30 has a high moisture content. The path through the dust collector 83 is preferred when the-air and dust passing through the outlet 30 has a low moisture content. If a high-moisture air and dust mixture were passed through the dust collector 83, it would tend to gum up the separator bags 86, such that these could not be efficiently cleaned by the blow-back process. As for the passage of a moisture-free mixture through the other path (that including the swirler unit 44 and the demister unit 49), the fact that the dust in the air does not it- 6 eterious effects will be noticed in the equipment itself.

Thus, the great versatility of the mobile vacuum unit disclosed herein adds considerably to its usefulness in a large variety of industrial waste: conditions.

Attention is now directed more closely to the collecbeen drawn in FIG. 2) and a dumping position in which rating efficiency of the swirler unit 44, although no delit is rotated between about 20 and 30 counterclockwise from the position shown in FIG. 2. The collector box 15 has a dumping opening 93 through which materials accumulated in the box can exit gravitationally when the box is in the dumping position, and the box further includes a door 94, or other suitable closure member, adapted to cover the opening 93 when the box is in the collection position (that shown) and to uncover the opening when the box is in the dumping position. The door is drawn in broken lines in the position it takes up relative to the collector box 15 when the latter is rotated counter-clockwise into the dumping position.

The interior of the collector box 15 is divided into a first chamber 95 which is adjacent to and in communication with the opening 93, and a second chamber 97 which is adjacent the first chamber 95 and is divided from the first chamber by a panel 98 which hangs down gravitationally from a horizontal pivot axis 100.

While the box 15 is essentially square in vertical, lateral and horizontal section, it will be seen in FIG. 2 that the bottom of the collector box 15 has a step 102 between the first chamber 95 and the: second chamber 97, with the floor of the second chamber 97 being somewhat higher than the floor of the first chamber 95. The panel 98 is adapted to close against the step 102 when the collector box 15 is in the collection position in which it is shown in FIG. 2.

From the top of the panel 98, a fixed wall portion 103 extends upwardly to the location of a fixed horizontal partition 104. Essentially, the fixed horizontal partition 104 defines the upper limit of the second chamber 97.

Vertically aligned with the fixed wall portion 103 is a coarse screen or filter panel 106 which is pivoted about a horizontal axis 107 for movement between the solid-line position shown in FIG. 2 and the dotted-line position shown in FIG. 2. An upper screen 108 extends upwardly from the top of the panel 106 when it is in its normal, closed position (solid-line position in FIG. 2).

From the top wall 110 of the collector box 15 an oblique panel 112 extends forwardly and downwardly to join the forward wall 114 of the collector box 15. The

oblique panel 112 meets the forward wall 114 above the location of the fixed horizontal partition 104.

Mounted in and passing through the fixed horizontal partition 104 is at least one separating unit 116 of the kind commonly referred to in the trade as a cyclone scrubber. This separating unit 116 includes an outer cylindrical housing 118, a lower conical converging nozzle 120, a centrally supported outlet pipe 122 coaxial with the cylindrical housing 118 and extending upwardly thereabove, and a plurality of helical vanes 124 positioned between the outlet pipe 122 and the cylindrical housing 118 at the upper extremity of the latter.

As seen, the outlet pipe 122 extends through the oblique panel 112, whereby air exiting through the outlet pipe 122 enters the space above and to the right of the oblique panel 112. Apart from the outlet pipe 122, the obliquie panel 112 completely isolates the inlet 29 from the outlet 30.

With the collector box in the collection position as shown in FIG. 2, and with the door 94 and the panel 93 in their vertical positions as shown in solid lines in FIG. 2, the action of the collector box 15 is as follows. The snorkel 24 draws a mixture of air, dust, particulate material and possibly moisture upwardly and debouches it into the first chamber 95 of the collector box 15. Into the first chamber 95 are deposited the heavier or coarser materials, and these accumulate and build up at the bottom of the first chamber 95. The air and the remaining particulate material not deposited in the first chamber 95 pass through the filter panel 106 and the upper screen 108 into the area directly above the fixed horizontal partition 104. The air-dust mixture then passes between the outlet pipe 122 and the cylindrical housing 118 and is caused to swirl or rotate by the helical vanes 124, as shown by the directional arrows. This swirling action causes a centrifugal separating process to take place, in which the heavier dust particles are thrown outwardly, and fall downwardly through the nozzle 120 to collect at the bottom of the second chamber 97. Any appreciable quantities of moisture or other liquid entrained in the air passing into the separating unit 116 is also accumulated in the bottom of the second chamber 97. Due to the high efficiency of the separating unit 116 in removing moisture, it usually happens that the material collected in the bottom of the second chamber 97 has a higher moisture content than that collected in the bottom of the first chamber 95. The air from which the material in the bottom of the second chamber 97 has been separated passes upwardly through the outlet pipe 122, emerges above the oblique panel 112, and passes directly through the outlet opening 30 of the collector box 15.

During the dumping operation for the collector box 15, two effects are created by the structure just described, both of which effects tend to promote a thorough and efficient removal of all of the accumulated material in both of the chambers 95 and 97.

As the collector box 15 tilts upwardly (moves in the counter-clockwise direction about the horizontal axis 92), the door 94 swings outwardly to its open position (an intermediate stage being shown in broken lines), and at the same time the panel 98 begins to exert a leftward pushing force on the accumulated material in the bottom of the first chamber 95, because gravitational forces are tending to make the panel 98 pivot clockwise with respect to the collector box 15. it will be understood that, in the absence of any restraining forces, both the door 94 and the panel 98 would tend to remain at all times vertical.

As the bottom of the panel 98 begins to move leftwardly into the first chamber 95, it automatically exerts a shoving pressure against the accumulated material in that chamber, and at the same time it permits the more aqueous and thus more mobile material accumulated in the bottom of the second chamber 97 to pass under the panel'98 and into the first chamber 95. Because of the step 102, the accumulated material in the bottom of the second chamber 97 has the equivalent of a head" with respect to the material in the first chamber, and because material in the second chamber is more liquid, it.

will tend to both mix with and pass underneath the material in the first chamber 95, thereby irrigating the same and facilitating the dislodgement of that coarser material through the opening 93 now uncovered by the door 94. It will further be realized that the head represented by the step 102 is additive to the natural elevation of the second chamber above the first chamber due to the counter-clockwise rotation of the collector box 15 with respect to the elongated frame 12.

It is to be understood that there may be more than one of the separating units 116 located in the second chamber 97. If more than one are to be used, they would preferably be aligned in the direction normal to the drawing sheet in FIG. 2, so that the separating unit 116 drawn in that figure would appear exactly aligned with any others provided.

If desired, positive means for opening and closing the door 94 can be provided, one reason for this provision being the desirability of obtaining access to the interior of the collector box 15 when the same is in its normal collection position, for such reasons as cleaning or repair. To accomplish this, cylinder means 126 can be provided as shown in FIG. 1.

A further cylinder 128 shown in FIG. 2 is provided for moving the collector box 15 between its collection position and its dumping position.

Provided in the box 15 is a pivotal locking means 126 which is shown to greater scale in FIG. 3. As seen, the panel 98 has a protruding L-bar or equivalent member 99 welded or otherwise affixed along its lower, horizontal edge 130. A shaft 132 is mounted for manual rotation in at least two bearing members 134 (only one visible in the figures) upstanding from the floor 135 of the box 15 in the first chamber thereof. Fixed to the shaft 132 for rotation therewith are a plurality of cam members 137 each having a camming edge 138 adapted to contact the L-bar 99 with a point contact. Preferably, all edges of each cam member are knife edges, to facilitate movement of the cam members through an accumulation of particulate material at the bottom of the first chamber 95. As can be seen, rotation in the clockwise sense of the shaft 132 will cause the cam members 137 to urge rightwardly against the panel 98 thus closing it securely against the step 102. Conversely, counter-clockwise rotation of the shaft 132 withdraws the edge 138 from the L-bar 99 and permits the panel 98 to move away from the step 102.

The shaft 132 extends outwardly through at least one side wall of the box 15, and has affixed to its end a manual crank (now shown).

If desired the first chamber 95 in the box 15 can be provided with flexible partitions depending from the top wall and extending lower than the inlet opening 29, in order to ensure some baffle action within the chamber 95 that will encourage the coarse materials to settle in the chamber 95 rather than to pass directly through the filtering panel 106.

What I claim is:

1. A mobile vacuum unit, comprising a mobile frame, a collection box mounted on said mobile frame, a snorkel communicating with said collection box and adapted to draw air and entrained materials into said box through suction, said box being adapted at intervals to dump materials contained therein, an outlet from said box leading to a two-way separating valve;

a first conduit leading from said valve to the intake of a swirler unit having means for capturing airentrained particles in a rotating stream of liquid, the outlet from said swirler unit leading through a second conduit to the tangential inlet to a demister unit having an exhaust outlet for gas at the top and a collection chamber for liquid at the bottom, pump means for recirculating liquid from said collection chamber to said swirler unit to enter said rotating stream of liquid, a third conduit from said exhaust outlet to one inlet of a two-way combining valve;

a fourth conduit leading from said two-way separating valve to the inlet of a bag filter unit, a fifth conduit leading from the outlet of said bag filter unit to the other inlet of said two-way combining valve, the outlet of said two-way combining valve being in communication with the inlet to a screen filter unit, the outlet of said screen filter unit communicating with the suction inlet of an air-pump, the outletof said air pump exhausting through muffling means to the atmosphere, and means for powering said air-pump.

2. A mobile vacuum unit as claimed in claim 1, in

which the collection box is mounted to said vacuum unit for pivotal movement about a horizontal axis be tween a collection position and a dumping position, and having a dumping opening through which said materials contained therein can exit gravitationally when the box is in the dumping position, a closure member adapted to cover the opening when the box is in the collection position and to uncover the opening when the box is in the dumping position, the box having a first chamber adjacent to and in communication with said dumping opening, a second chamber adjacent the first chamber and divided therefrom by a panel depending gravitationally from a horizontal pivot axis, the panel substantially isolating lower portions of the chambers from one another when the box is in the collection position but permitting communication between the lower portions of the chambers when the box is in the dumping position, said outlet from said box communicating with the second chamber, said snorkel communicating with said first chamber of the collection box, the collection box providing a passage for air from theefirst to the second chamber above the said panel, the first chamber being adapted to accumulate coarse solids entrained in the entering air, the second chamber containing separation means to facilitate the separation from the air of liquids and finer solids, the second chamber being so disposed with respect to the first chamber that upon pivoting of the box from the collection to the dumping position, the material collected in the second chamber tends to pass gravitationally into the first chamber under said panel, thus irrigating the coarser material in said first chamber and facilitating its dislodgement through said dumping opening.

3. A mobile vacuum unit, comprising a mobile frame,

a collection box mounted on said mobile frame, a snorkel communicating with said collection box and adapted to draw air and entrained materials into said box through suction, said box being adapted at intervals to dump materials contained therein, an outlet from said box leading to a two-way separating valve;

a first conduit leading from said. valve to first means adapted to mix materials passing through said first conduit with liquid in a highly agitated state, thereby to entrain in the liquid particulate matter in said materials, second means for separating liquid and entrained particulate matter from gas in said materials,

second conduit for carrying said separated gas to one inlet of a two-way combining valve,

a third conduit leading from said two-way separating valve to the inlet of a bag filter unit, a fourth conduit leading from the outlet of said bag filter unit to the other inlet of said two-way combining valve, the outlet of said two-way combining valve being in communication with the suction inlet of an airpump, the outlet of said air pump exhausting through muffling means to the atmosphere, and means for powering said air-pump. 

1. A mobile vacuum unit, comprising a mobile frame, a collection box mounted on said mobile frame, a snorkel communicating with said collection box and adapted to draw air and entrained materials into said box through suction, said box being adapted at intervals to dump materials contained therein, an outlet from said box leading to a two-way separating valve; a first conduit leading from said valve to the intake of a swirler unit having means for capturing air-entrained particles in a rotating stream of liquid, the outlet from said swirler unit leading through a second conduit to the tangential inlet to a demister unit having an exhaust outlet for gas at the top and a collection chamber for liquid at the bottom, pump means for recirculating liquid from said collection chamber to said swirler unit to enter said rotating stream of liquid, a third conduit from said exhaust outlet to one inlet of a two-way combining valve; a fourth conduit leading from said two-way separating valve to the inlet of a bag filter unit, a fifth conduit leading from the outlet of said bag filter unit to the other inlet of said two-way combining valve, the outlet of said two-way combining valve being in communication with the inlet to a screen filter unit, the outlet of said screen filter unit communicating with the suction inlet of an air-pump, the outlet of said air pump exhausting through muffling means to the atmosphere, and means for powering said air-pump.
 2. A mobile vacuum unit as claimed in claim 1, in which the collection box is mounted to said vacuum unit for pivotal movement about a horizontal axis between a collection position and a dumping position, and having a dumping opening through which said materials contained therein can exit gravitationally when the box is in the dumping position, a closure member adapted to cover the opening when the box is in the collection position and to uncover the opening when the box is in the dumping position, the box having a first chamber adjacent to and in communication with said dumping opening, a second chamber adjacent the first chamber and divided therefrom by a panel depending gravitationally from a horizontal pivot axis, the panel substantially isolating lower portions of the chambers from one another when the box is in the collection position but permitting communication between the lower portions of the chambers when the box is in the dumping position, said outlet from said box communicating with thE second chamber, said snorkel communicating with said first chamber of the collection box, the collection box providing a passage for air from the first to the second chamber above the said panel, the first chamber being adapted to accumulate coarse solids entrained in the entering air, the second chamber containing separation means to facilitate the separation from the air of liquids and finer solids, the second chamber being so disposed with respect to the first chamber that upon pivoting of the box from the collection to the dumping position, the material collected in the second chamber tends to pass gravitationally into the first chamber under said panel, thus irrigating the coarser material in said first chamber and facilitating its dislodgement through said dumping opening.
 3. A mobile vacuum unit, comprising a mobile frame, a collection box mounted on said mobile frame, a snorkel communicating with said collection box and adapted to draw air and entrained materials into said box through suction, said box being adapted at intervals to dump materials contained therein, an outlet from said box leading to a two-way separating valve; a first conduit leading from said valve to first means adapted to mix materials passing through said first conduit with liquid in a highly agitated state, thereby to entrain in the liquid particulate matter in said materials, second means for separating liquid and entrained particulate matter from gas in said materials, a second conduit for carrying said separated gas to one inlet of a two-way combining valve, a third conduit leading from said two-way separating valve to the inlet of a bag filter unit, a fourth conduit leading from the outlet of said bag filter unit to the other inlet of said two-way combining valve, the outlet of said two-way combining valve being in communication with the suction inlet of an air-pump, the outlet of said air pump exhausting through muffling means to the atmosphere, and means for powering said air-pump. 